JP2008155907A - Electrical heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrical heating device for an automobile capable of preventing the structure-borne noise or the sound wave generated by the air flowing therein or both from reaching a person in the automobile. <P>SOLUTION: The electrical heating device has a layer structure held by a retaining device. The layer structure has several heat generating elements and heat dissipating elements 4 between the heat generating elements, and a control device 16 for controlling the heat generating elements. The heating device has a sound deadening housing 14, which circumferentially encloses the control device 16 and by which sound waves produced by the control device 16 are deadened. This measure is capable of preventing the noise generated from a structure or the sound wave generated by the air flowing through the electrical heating device or both from reaching a person in the automobile. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The invention relates to an electric heating device, in particular for motor vehicles, with a layer structure held by a holding device, the layer structure comprising several heat generating elements and a heat dissipating element between these elements. The present invention relates to an electric heating device including a control device that controls a heat generating element.

  An electric heating device having this feature is known, for example, from Patent Document 1 by the present applicant.

  In conventional heating devices, the individual layers of the layer structure are bonded to each other, particularly when the layer structure is housed in a closed frame forming a holding device, or with the spring pretensioned. Can be pressed. The individual electric heat generating elements are held in a state of being isolated from each other in a holding device, and generally an electric contact element is provided on the side surface of the layer structure, for example, in the longitudinal direction of the layer structure. The specific heat generating element can be electrically connected to the electric system of the vehicle via the electric contact element.

  In order to form the heat generating element, a resistance heating element, that is, a so-called PTC heating element is usually used, and this element can reliably prevent overheating of the heat generating element due to its control characteristics. Each of the heat generating elements usually comprises a number of PTC heating elements arranged to overlap each other in the longitudinal direction of the layer structure. The heating element is laid flat on a conductive and generally good heat conducting surface, through which electric energy is supplied to the heat generating element and the generated heat is transferred by heat conduction. Dissipated. This flat surface is usually formed by a heat dissipating element, for which purpose the heat dissipating element is provided with a strip of sheet metal in contact with the heat generating element on its outer side, In particular, it is connected as a separate component or integrated into a heating rib or plate extending transversely to the layer structure. When the flat surface is formed by a flat strip sheet metal, the strip sheet metal is generally assigned to the heat generating element. In this regard, the strip sheet metal can form a prefabricated unit with the PTC heating element.

  The electric heating device includes a control device that controls the heat generating element in order to perform open loop control or closed loop control. In this case, the control device can comprise an electronic control element or a conventional relay, or both.

  Automotive electric heating devices are made as modules according to the general trend in the automotive industry, i.e. the control device is attached to the holding device as part of the electric heating device or arranged in some form adjacent to the holding device Often done. For example, Patent Document 2 discloses a device in which a control device for controlling a heat generating element is formed using a power transistor and arranged in a frame, and a cooling fin is provided on a side surface facing a layer structure. . An arrangement similar to this is known from US Pat. No. 6,057,056, which can also be regarded as the same type, and the control device is likewise formed by a power transistor and housed in a frame. Further, in this arrangement, in order to provide the control device in the holding device, it is necessary to release the heat loss caused by the transistor to the air flowing in the electric heating device. An alternative design method is known from patent document 1 mentioned at the beginning, in which the control device is housed in a separate housing on the side of the frame and is mainly formed from a switching relay, Loss is not dissipated.

In arrangements in which the control device is in or adjacent to the holding device, in particular arrangements in which the control device is mounted directly on the holding device, the noise generated during switching is transferred to the passenger compartment by the air carried There is a problem that it is relatively easy to reach and noise can be heard by the vehicle occupant. However, the sound generated by the control device may be transmitted to the vehicle interior through the wall of the air conditioning duct as, for example, noise generated from a structure (structure-borne noise). In this case, even if the auditory noise generated by the control device is relatively small, it may be amplified by the walls of the hollow air conditioning duct, so that the auditory noise of the vehicle occupant is It does not only occur when the conventional mechanical switching relay switches.
European Patent No. 1,691,579 European Patent No. 1,157,867 European Patent No. 1,492,384

  An object of the present invention is to reduce the influence of auditory noise on a vehicle occupant. This object is solved according to the invention by an electric heating device with the features of claim 1.

  Preferred further embodiments are described in the dependent claims.

  In the case of the electric heating device according to the invention, the control device is essentially surrounded by a silencer housing which is closed around. The silencer housing can completely or almost completely surround the control device, and is configured to absorb at least a part of sound waves emitted from the control device. In this regard, both sound waves propagating as noise generated from the structure without a silencer housing and sound waves carried by the air flowing through the electric heating device are preferably absorbed. The silencer housing needs to be formed so that sound waves generated by the control device are immediately absorbed by the control device. The electric heating device according to the invention has proven to be particularly effective in embodiments in which the control device is arranged on the side of the holding device and connected to the holding device. Specifically, in the case of such an embodiment, there is a problem that sound waves reach the passenger compartment through the air flowing through the electric heating device without being disturbed so much as noise generated from the structure.

  In the following, embodiments will be described with reference to the drawings to show further advantages and details of the present invention.

  FIG. 1 shows the main parts of an electric heating device. The device comprises a plastic housing 2 consisting of two parts, in which a layer structure having several heat generating elements and a heat dissipating element arranged between them is held. And is pretensioned by a spring device (to be described in detail later). The heat dissipation element 4 can be regarded as an elongated sheet metal that is bent and curved. A heat generating element (not shown) extends in parallel with the vertical column 6 between the elongated sheet metal behind the vertical column 6 passing through the housing opening 8 formed in the plastic housing 2. Not exist). In the central region of the housing opening 8, the layer structure is omitted so that the spring piece 10 is visible, and a spring web protrudes inward from the spring piece 10. The spring piece 10 is inserted through an insertion groove 12 formed in the side surface, as described in European Patent 1,432,287 by the applicant.

  A silencer housing 14 is arranged on the side of the plastic housing 2 surrounding the layer structure. The silencer housing 14 essentially comprises a second housing element that houses the control device 16 and a first housing element that is arranged between the second housing element and the plastic housing. The reference number of the first housing element is 18 and the reference number of the second housing element is 20. The first housing element 18 is connected to both the second housing element 20 and the plastic housing 2.

  The first housing element 18 has a flange segment 22 on the bottom surface facing the plastic housing with a hole for attaching this embodiment to an air conditioning duct of an automobile. Further, the first housing element 18 is formed with an outer peripheral sealing groove 24 on its bottom surface, and this groove 24 is mutually engaged with a raised portion formed in the air conditioning duct to seal the plastic housing 2. To do. The plastic housing 2 is pushed into an air conditioning duct that extends laterally to the outside. Furthermore, a T-shaped latching tongue 26 projects downward from the bottom surface of the first housing element 18 which is a single part, and this tongue latches the plastic housing 2.

  The first housing element 18 is formed with a single part housing cover 30 having a rectangular bottom region on the upper side opposite the bottom surface (FIG. 2). Reinforcing ribs 28 are formed on the housing cover to be strong, and the flange segments 22 are arranged to face each other.

  The housing cover 30 fits between a collar 32 extending outside the periphery of the second housing element 20 and a muffler plate 34 housed in and projecting from the second housing element 20. Apart from the silencing plate 34 covering the inner circumference of the silencing housing 14 as shown in FIG. 2, further silencing plates can be provided inside the housing cover 30 or at the bottom of the second housing element 20. . However, in the illustrated embodiment, the silencer plate 34 is not provided at the bottom of the second housing element 20, and this design will be described later. The housing cover 30 may include a silencer plate located near the side surface of the silencer plate 34 provided in a circumferential shape.

  The sound deadening plate 34 is cut from a foam plastic having a relatively high density, and is fitted into the second housing element 20 accurately. In the illustrated embodiment, the silencer plate 34 has a thickness of 4 mm to 6 mm, preferably 5 mm. As a further measure for the silencing enclosure inside the silencing housing 14, a silencing layer is provided between the collar 32 and the circumferentially disposed silencing plate 34, and this silencing layer is, for example, an embedded seal ( inlaid seal) or a muffler element formed in the first housing element 18 or the second housing element 20 by two-component injection molding. This silencer is preferably either on the side of the housing cover 30 or at the sealing edge 36 of the second housing element 20 which is surrounded by a collar 32 as shown in FIG. It is formed according to the type of sealing lip. By this sound deadening layer, the two housing elements 18, 20 are joined in a sound dead state.

  As is apparent from FIG. 3, the holding part 38 of the conductive contact spring 40 protrudes from the bottom 52 of the second housing element 20. Contact protrusions that are electrically connected to the individual heat generating elements engage with these contact springs 40, and the contact protrusions are regularly formed of strip-shaped sheet metal. , At least a part of the positioning surface of the PTC heating element is formed, and is drawn sideways through the side surface of the plastic housing 2. To achieve this, the first housing element is provided with a groove-like insertion opening 42 as shown in FIG. 2, in which the longitudinal web 44 lies laterally on the bottom surface of the first housing element 18. The recesses are spaced apart to form a single piece, and the web edge 46 is conical, thereby forming a funnel shape in the insertion opening 42 and thus the contact point. The protrusion is easily inserted into the insertion opening 42. As is apparent from FIG. 3, the holding portion 38 is formed by a grooved tube 48, and this tube 48 is firmly formed in the lower portion thereof by the reinforcing rib 50 from the bottom portion 52 of the second housing element 20. Has been. These tubes 48 are provided with a lateral groove 54, which is formed at a position where the reinforcing rib 50 is extended, and penetrates a part of the groove 48. In addition, the tube 48 has a cable groove 56 that is cut perpendicular to itself and extends downward to near the bottom 52.

  An inner housing 60 is inserted into the second housing element 20 and this inner housing 60 is shown in more detail in FIGS. The inner housing is preferably made of a sound deadening material, for example an injection molded part of foam plastic. The inner housing 60 has an inner housing base 62 having an essentially U-shaped cross section, and an inner housing cover 64 is rotatably supported on the base 62. In the inner housing base 62, three control element accommodation spaces 68 separated by a partition wall 66 are formed. Each of the control element receiving spaces 68 can have further sound deadening partitions, which are shown by way of example in FIG. The side surface of the side wall 72 of the inner housing base 62 forms a positioning surface 74 of the circuit board 76, and the partition wall 66 extending perpendicularly to the circuit board 76 protrudes from the positioning surface 74, and the circuit board 76. Are separated from each other by a partition wall 66. A circuit board 76 is positioned on the positioning surface 74, and FIG. 4 shows only one circuit board 76 as an example. In this figure, other circuit boards are omitted.

  As is apparent from the figure, the side surface of the partition wall 66 and the upper surface of the circuit board 76 are substantially at the same height. Above this surface is a closed inner housing cover 64. The circuit board 76 and the inner housing cover 64 protrude beyond the side wall 72. Using this protruding portion of the circuit board 76, the electrical connection leads 78, 80 and the control lead 82 are connected. Although not shown in the drawing, the control element (for example, relay) protrudes from the inside of each circuit board 76 into the control element accommodation space 68. Each control element of each circuit board 76 is housed in a control element housing space 68 that is separated by a partition wall 66 and divided by another partition wall 70.

  The connection lead 80 that communicates with the circuit board 76 is formed by an extension of the central feeder cable 84. A further ground lead 86 leads to the inner housing 60. Each of the ground lead 86 and the connection lead 78 protruding from the circuit board 76 has one contact spring 40 electrically connected to the corresponding leads 78 and 86 at the end. Leads 78 and 80 connected to the circuit board 76 extend essentially parallel to the side wall 72 and then pass in front of a further side wall 88 that extends laterally through the housing 14 when fitted. .

  As can be seen in particular in FIG. 5, the circuit board 76 protrudes beyond the respective connection leads 78, 80 at the connection point. Further, the inner housing cover 64 protrudes beyond the inner housing 60 and the circuit board 76 at the connection point. The embodiment of the inner housing 60 shown in FIG. 5 can be formed as a pre-assembled component. In this regard, it is sufficient if the inner housing cover 64 is located on the circuit board 76. There is no particular need to fix the inner housing cover 64 to the inner housing base 62. However, such fixation can be achieved by prefabricated components.

  To attach the inner housing 60 to the second housing element 20, the second housing element 20 is provided with a socket at the bottom 52, and when inserted into the housing 14, the protruding edge of the inner housing cover 64 is removed. The socket can be fitted together with the end of the circuit board 76. In this arrangement shown in FIG. 3, the inner housing cover 64 is located on the corresponding silencer plate 34. The assembled inner housing 60 is in contact with the bottom 52 made of plastic only on the side of the inner housing cover 64 made of sound deadening material. The sound deadening material is a plastic that does not contain silicon, and is preferably a relatively soft plastic such as polyurethane, so that the material that forms the inner housing 60 ensures a certain degree of sound deadening of the inner housing 60. Is done. Polyurethane plastics having a hardness (Shore A) of 50 to 90 have been found to be practical. The socket is dimensioned such that the inner housing cover 64 fits snugly with the circuit board 76. Optionally, press fit can be achieved such that the inner housing 60 fits into the silencer housing 14 via a socket with the silencer material of the inner housing cover 64 slightly compressed. The socket can be formed by injection molding as a single piece in the housing 14, for example, by a recess, rib, web, or similar shape in the bottom 52. Alternatively, a socket can be formed by one silence plate 34 or between multiple silence plates.

  During assembly of this embodiment, first the prefabricated components are inserted into the second housing element 20. The contact spring 40 is then pushed into the respective lateral groove. On the other hand, the connection lead 78 or the ground lead 86 is pushed into the cable groove 56 in which they are accommodated.

  The second housing element 20 has a first cable opening 90 cut out for leading the leads 80 or 86 out. A second cable opening 92 for the control lead 82 is also cut away. Each of the two openings 90, 92 is covered on the upper side by the first housing element 18, thus simplifying the insertion of each lead 80, 82, 86.

  The embodiment presented above has the advantage that the individual circuit boards 76 are housed in separate control element housing spaces with associated control elements. A circuit board common to all of the control elements of the control device is provided to avoid situations where the emitted sound is unnecessarily amplified by the resonating body. Since the inner housing 60 is formed as a prefabricated component with the associated circuit board 76 and leads 78, 80, 82, 86 connected thereto, the inner housing 60 can be prefabricated first. By fitting the inner housing cover 64 to the inner housing base 62, the precision control elements are sealed. The prefabricated components are securely attached to the silencer housing 14 to protect the control element from impacts. In addition, the precise section of the circuit board is prevented from being soiled. The only portion of the circuit board 76 that is not sealed is the section that protrudes from the inner housing base 62, and there is no precise electrical or electronic area in this section. Since the socket is formed in the second housing element 20 so that the prefabricated inner housing 60 can be inserted, the inner housing and the silencer housing 14 can be easily connected.

  While the sound producing control element is surrounded by the inner housing, it is supported by the sound deadening housing 14 in a state of being muted by the inner housing cover 64 and further surrounded by the sound deadening plate 34, so that the best sound deadening is achieved. Is achieved. In particular, sound propagation is also reduced by the hermetic sealing of the housing. In this regard, a flat plug contact that is inserted from the radiator into the housing 14 passes through a lip seal formed, for example, by two-component injection molding. By using an appropriate seal, a seal can be provided in the opening 90 or 92 for passing the leads 80, 86, and this seal is formed in the housing 14 by two-component injection molding.

  Due to the special design of the tube 48, the assembly of contact springs 40 introduced with prefabricated components can be simply and accurately fitted. In this design, it is also easy to automatically insert the contact spring 40 into the tube 48.

  The subunits of the control device 16 are accommodated in the control element accommodation spaces 68, respectively. Each of the control device subunits is individually housed in the inner housing 60 and is itself silenced. The control unit subunit preferably controls proportionally the total heating power of the electric heating device by means of an open loop or a closed loop. In the illustrated embodiment, three control subunit devices are provided, each controlling one third of the heating output of the entire heating device. In this manner, the electrical energy consumed by the electric heating device can be well adapted to the generator output of the automobile. In the illustrated embodiment, the electrical heating power can be switched to 1/3, 2/3, or 3/3 of the maximum heating power. However, considering the switching capacity of the relay, the heating output of the switching circuit can be designed differently from the others. The heating output grading of one switching circuit is only divided into three switching circuits in this embodiment, but using appropriate on / off switching of individual switching circuits, The total heating output should be chosen so that it can be switched in as few steps as possible. In the illustrated embodiment, only relays are used as control elements.

It is a side perspective view of this embodiment. It is a disassembled perspective view of the housing surrounding the control apparatus by this embodiment. FIG. 3 is a perspective view of a housing element of the housing according to FIG. 2. It is a perspective view of the inner side housing of this embodiment shown in FIGS. It is a top view of the opposite side of the inner housing shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Plastic housing 4 Heat dissipation element 6 Longitudinal support | pillar 8 Housing opening 10 Spring piece 12 Insertion groove 14 Silent housing 16 Control apparatus 18 1st housing element 20 2nd housing element 22 Flange segment 24 Sealing groove 26 Latching tongue 28 Reinforcement rib 30 Housing cover 32 Collar 34 Sound deadening plate 36 Sealing edge 38 Holding part 40 Contact spring 42 Insertion opening 44 Vertical web 46 Web edge 48 Tube 50 Reinforcement rib 52 Bottom part 54 Horizontal groove 56 Cable groove 60 Inner housing 62 Inner housing base 64 Cover 66 Partition wall 68 Control element receiving space 70 Further partition wall 72 Side wall 74 Positioning surface 76 Circuit board 78 Connection lead 80 Connection lead 82 Control lead 84 Feeder case Le 86 Ground lead 88 vertical sidewall 90 first cable opening 92 the second cable opening

Claims (14)

Electrical heating device, in particular for motor vehicles, with a layer structure held by a holding device (2), said layer structure being arranged between several heat generating elements and these elements A heat dissipating element (4) and a control device (16) for controlling the heat generating element, the control device (16) being surrounded by an essentially closed housing (14) In the electric heating device,
The electric heating device is characterized in that the control device (16) is supported in the housing (14) by a muffler element (34) as an intermediate layer.   The housing (14) comprises a first housing element (18) provided with attachment means (26) for attaching the housing (14) to the holding device (2), a second housing element (20), The second housing element (20) is connected to the first housing element and houses the control device (16), and the control device (16) The electric heating device according to claim 1, wherein the electric heating device is supported in a state where the electric heating is performed.   3. Electric heating device according to claim 1 or 2, characterized in that the housing elements (18, 20) are arranged on both sides of a sound deadening layer arranged therebetween.   The electric heating device according to any one of claims 1 to 3, characterized in that the second housing element (20) is covered by a silencer plate (34).   At least one inner housing (60) holding the control device (16) is housed in one of the housing spaces of the silencer housing (14) formed by the silencer plate (34). The electric heating device according to any one of claims 1 to 4, wherein the electric heating device is provided. Comprising at least one circuit board (76) on which the control elements are mounted,
The inner housing (60) is configured to achieve silencing;
At least one circuit board (76) covers a control element receiving space (68) defined by the inner housing (60);
The electric heating device according to claim 5. Comprising several individually controllable heating blocks, said heating block comprising at least one heat generating element and individual control devices assigned to these heating blocks;
7. The electric heating device according to claim 6, wherein each of the control devices is formed by a control device subunit that is held in a silenced state. The circuit board in which an individual control element accommodation space (68) is provided for each of the control device subunits, and each of the individual control element accommodation spaces (68) is allocated to the control device subunit. (76) covered,
The circuit board (76) is separated from each other by a partition wall (66) formed by the inner housing (60) and projecting from a positioning surface (74) for the circuit board (76). And
The electric heating device according to claim 7.   The electric heating device according to any one of the preceding claims, characterized in that it has a housing cover (64) covering the back side of the circuit board (76) in the absence of a control element. The inner housing cover (64) is in contact with the at least one partition wall (66);
The circuit board (76) protrudes beyond the inner housing (60) to allow connection leads / control leads (78, 80, 82) to be connected;
The electric heating device according to claim 8 or 9, characterized in that. The inner housing cover (64) is more than the circuit board (76) in the section of the circuit board (76) where at least the circuit board (76) protrudes from the inner housing (60). And also sticking out
The circuit board (76) and the inner housing cover (64) are engaged at their ends with sockets formed in the silencer housing (14);
The electric heating device according to claim 9 or 10, characterized by the above. The inner housing cover (64) is rotatably supported by the inner housing (60);
The control device (16), to which the connection leads / control leads (78, 80, 82, 84) are attached, together with the inner housing cover (64) closing the inner housing (60), is a prefabricated component. Being formed,
The electric heating device according to any one of claims 9 to 11, wherein The second housing element (20) has a retaining part (40) for a contact spring (40) connected to the end of each of the connecting leads (78, 80) coming out of the control device (16). 38), the contact spring (40) can be pushed into the holding portion;
Corresponding to the holding part (38), the housing element (18) is provided with an insertion opening (42) that is cut out for a protruding part, the protruding part being connected to the contact spring (40). And can be electrically connected to the heat generating element;
The electric heating device according to any one of claims 1 to 12, wherein The retaining portion (38) is formed by a grooved tube (48), the grooved tube protruding from the bottom (52) of the second housing element (20), and 14. Electric heating device according to claim 13, characterized in that it is formed as a single part in two housing elements (20).

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